[Vinnie R.]

Hello,

I was just curious about what is the input impedance and sensitivity of the Aksa 55?  

Has anyone tried using a passive preamp with an Aksa?  Was there
a loss in dynamics, or did it work well?  I'm sure the source has
a big influence as well.  Mine is 2Vrms output.

Thanks for all your input.

-Vinnie

[PSP]

Hi Vinnie,
I've been listening to my AKSA 55 in a passive configuration for several months (while I re-build my TLP into a seperate enclosure... this is not a big job but my work schedule is intense and so my audio projects can take a while)... so I have:

Source RCAs-->Grayhill Selector Switch-->DACT attenuator-->AKSA 55

In my case, this is all in one chassis, and signal leads are short.  Thus, the problems of cable capacitance and cable length do not apply in my case.  How does it sound?  Very, very nice, thank you.  If my passive-AKSA 55 was the only way I had ever heard my AKSA I would be a very happy man.  Problem is, I have also heard my AKSA driven by a Nirvana TLP and that sound was to die for (with a very small smidgeon of hum, that which I am currently plotting against!).  The passive setup was surgically clean, detailed, and utterly noise free.  Not sterile, not analytical, it made very, very nice music.  Addition of the Nirvana TLP brought palpability and emotion to the music though, and I like it better that way (even if it isn't the exact truth, it is musically true to me).  Analogy:  would you prefer that your true love look like "the truth" or would you like her to put on a little makeup, wear some nice underthingies, etc?

The decision is yours... my system sounded very, very nice in a passive configuration.  Maybe you should try it (it's easy enough) and see what you think.

Peter

[Grumpy_Git]

Vinne, a quick look at the FAQs on Hughs website reveals:

-------------------------------------------

With a gain of 32dB and an input impedance of 47k

AND

In both models of the AKSA, distortion does not exceed 0.2% at any level.

---------------------------------------------

As for the passive option, its something that Hugh has recommended in the past though I'm sure he'd rather sell you a GK1 now!!

I'm waiting on the cash for 3 matched Panasonic stereo pots so I can passivly connect things and also contemplate AKSA HT Heaven in the future with a processor.

Hope this helps.

Nick.

[Vinnie R.]

Peter,

What value stepped attenuator are you using (10K, 50K, 100K)?  What kind (series, parallel, shunt)?

Sounds like you are very happy with it, but how is the bass punch using a passive vs. active?  I know this has a lot to do with impedance matching of the source, volume control, and amp.  If done correctly (still trying to figure out what defines this), I have read many favorable things about passive preamps, like yours.  If done incorrectly (bad impedance matching), I have read negative things such as lack of bass punch and articulation, rolled off highs, uninvolving sound.  

I understand that an active preamp can add coloration to the sound that is actually very musical and enjoyable.  I don't consider myself a "distortion ratings freak" who only looks at numbers.  I am much more concerned with how musically enjoyable the sound is even if there is a loss in accuracy.  

Thanks for your comments!

Vinnie

[Vinnie R.]

Vinne, a quick look at the FAQs on Hughs website reveals:

-------------------------------------------

With a gain of 32dB and an input impedance of 47k

AND

In both models of the AKSA, distortion does not exceed 0.2% at any level.

---------------------------------------------

Doh!  I overlooked this on Hugh's website.

Thanks Nick!

-Vinnie

[PSP]

Hi Vinnie,

What value stepped attenuator are you using (10K, 50K, 100K)? What kind (series, parallel, shunt)?

I used a 20K DACT in series configuration; chosen because that's what Hugh recommends with the TLP.  Someday I'll try a shunt setup (worked well with the Foreplay), but it's not high on my priority list.

Sounds like you are very happy with it, but how is the bass punch using a passive vs. active? I know this has a lot to do with impedance matching of the source, volume control, and amp. If done correctly (still trying to figure out what defines this), I have read many favorable things about passive preamps, like yours. If done incorrectly (bad impedance matching), I have read negative things such as lack of bass punch and articulation, rolled off highs, uninvolving sound.

In my case (equivalent of very short interconnects) I would not say that there were any definable deficincies in the passive setup... highs were not rolled off, bass good too.  Addition of the TLP Nirvana lead to a bit more bass (without any decrease in bass articulation) and significantly more involvement.  How the hell do you define "involvement"?  I can't tell you, I just liked listening more with the TLP Nirvana in the system.

Gotta go,
Peter

[Vinnie R.]

Today I bought a cheap 50K stereo carbon film pot and a 10K pot.
I hooked it up between my cdp and aksa 55 using el cheapo male and female RCA cords that match in quality of the pots.  I first tried the 50K pot.
To my surprise, it sounded pretty damn good.    The dynamics of the
music were definitely there, with ample bass that was fairly punchy
and tight.  The highs were more detailed and at times a little sharper
than what I was used to.  
I then tried the 10K pot and it sounded even better!  The bass is awesome,
both tight and punchy as ever.  The dynamics were also better than ever,
with fast transients that were alive!    However, the treble still remained
pretty much the same as the 50K pot.  Its not bad at all, but there is
more bite in the treble than with my NAD preamp.  It could just be that the passive volume control is more revealing of poorly recorded cd's.  
 
I am keeping in mind that I am using a dirt cheap carbon film 10K stereo pot.  If I were to use a 10K high quality stepped attenuator, I wonder how much better things will get?  Overall, the cheap pot I am using now  sounds better than my preamp, so this was a big surprise.    I didn't think a passive volume pot could bring such a beneficial change in the emotion of the music, wow!  

Without the preamp, I am hearing the Aksa 55 without any other influences on the sound other than the cdp, and this just demonstrates
how excellent the Aksa is, it's FANTASTIC sounding!  

I just wanted to report my findings to this group just in case others
are also considering a passive preamp.  I am definitely considering
either a goldpoint or DACT stepped attenuator.  I may or may not
put it in the chassis of the Aksa.    www.goldpt.com has a pretty cool
passive preamp that has either two or three inputs.  It looks like a
high quality build.  A stepped attenuator with a remote volume control
would be ideal, but I haven't seen any out there yet.  

-Vinnie

[Pleb Plebian]

Hi Vinnie;
I've played with the '55s in both passive and active mode...both std and bi-amped.
In every case, I preferred active (given a _very_ good pre :-) -including, as Peter noted, the TLP (std and Nirvana).
Against more mediocre pre's, passive won.
It really comes down to dynamics and imaging -plus the ability to drive active XO's etc easily (active) against "natural" tonality, where the music just seems to roll out of the speakers without hindrance (passive) - FWIW, only the GK and very expensive pre's IMO better a good passive at this...

As noted, passive is easy to try - FWIW, I'd go for a switched attenuator over a pot (check out recycled technology stores for excellent switches -I've got a beautiful NOS 1962 NOS telecomms one here - $12 NZD .... throwout prices!)

Have a play: lots to gain, little to lose except time!
-and yeah, both the 55 and 100's are sensitive enough to go LOUD on a passive from my CD player (speakers are 90dB efficient)
Cheers
-Darl

[harvardian]

Hi Vinnie,

Perhaps you have some time to help me work on a remote controlled switched attenuator. I have all of the parts, but have not completed the design.

Dale

[Vinnie R.]

Dale,

Absolutely!  I actually have been thinking of doing this myself sooner or
later, so I'll email you.

-Vinnie

[mb]

Pleb's comments match my experience very closely. If you're partial to the "sound" of passive attenuators, but don't want to miss the drive of an active, check out using a battery-powered high-speed buffer (EL2001, BUF834, etc) after the attenuator.

I've tried building low-gain opamp preamps, with battery supply, good caps, etc, but the results have always been, well, "transistory" in the negative sense -- grainy, fatiguing. Using identical power supply and switching to a unity buffer, the negatives disappeared, and the attenuator's true qualities can be revealed (positively) by AKSA. One friend even tried my buffer connected after his Foreplay variant, and it helped in the bass / drive department. FYI, I'm using (1) TKD 41-step attenuator (10k) - great refined sound, rather large and expensive, (2) Bourns 100k linear conductive plastic with 10k Holco lawfake (bought from Ben Duncan / UK ages ago). With active buffer, both sound excellent, with the TKD better all-around, but not by a large margin.

[Vinnie R.]

Thanks for the info everyone.

From just using a cheap 10K audio tapered stereo pot, I'm getting excellent dynamics, punchy bass, and great soundstage and
separation.  So far, the only thing not as great is a sharper
treble.  I'm not sure if this is due to the quality of the carbon film
pot, or just because I eliminated all the preamp circuitry?  

I'm going to have to try a 10K stepped attenuator passive preamp
because it has to be better than this cheap pot!  

I am very content with everything else and don't think I'll need to
go active again, unless it is a dynamite active preamp.  

Thanks again,

Vinnie

[Grumpy_Git]

Anyone got an explaination on law faking pots? I'm looking at a linear Vishay 10k dual gang.

Not sure how to go about picking a value for faking resistor, any help appreciated. Any Advice on the requirements for quality of the Resistors or if they can be el Cheapo??

Cheers

Nick.

[Larry]

I am very content with everything else and don't think I'll need to
go active again,

Q&A with an Audiophile Nervosa

Q: What is Audiophile NERVOSA?
A: Human beings of a certain kind of mental disorders. The symptoms include:
 - Calling all kind of stuff on CDs softwares;
 - Listening to noises and what sounds bad;
 - Changing hardware more frequently than music;
 - Buying the same title over and over again, from standard to Japanese pressing to 24bit remastered to XRCD to SACD ...

Q: What is your favorite MISTAKE?
A: Reading too deeply into reviews and forgotten that I’ve ears too.

Q: What are your most ANGUISH moments?
A: Messing up my perfect system and not able to get the sound back again.
 
Q: What do you FEAR most?
A: The shopkeeper telling me its out-of-print!

Q: When are you WEAKEST?
A: Knowing that there is an upgrade model available.

Q: What is your favorite LIE?
A: After this upgrade, I will not do it in the next 2 years.

[Vinnie R.]

So what are you trying to say Larry, that I have some
kind of "disorder?"  

[Larry]

So what are you trying to say Larry, that I have some
kind of "disorder?"  

If you are that kind of persons who can not sleep with a pot in the signal path, you will certainly "go active again" with your new attenuator to see how it would sound in a highly spoken pre, like GK-1, within "the next 2 years". Believe or not.

You haven't tried your attenuator in any active pres, have you?

[mb]

Anyone got an explaination on law faking pots? I'm looking at a linear Vishay 10k dual gang.

Not sure how to go about picking a value for faking resistor, any help appreciated. Any Advice on the requirements for quality of the Resistors or if they can be el Cheapo??

Cheers

Nick.

The general guideline is to use 100k linear, and something in the region of 10k lawfake. The Ben Duncan kit I bought years ago had 100k + 11k Holco resistors. A 10k linear will be much too low.

There is speculation that normal listening levels, the lawfake resistor quality contributes greatly (makes sense, electronics-wise, because it forms a major part of the input load), which allows you to use a lower cost pot. Don't skimp on the lawfake.

[DSK]

Grumpy_Git,
FWIW, friends of mine (with excellent ears) have experimented with law faking Vishay linear cermet pots and found the Vishay Sfernice log cermet pot (currently provided by Hugh with GK-1 Phase 1) to be better, and to be very close to the DACT series attenuator.

mb,
I see you are using the TKD 41-step series attenuator. I  considered this while designing my GK-1. For the moment I am using the cermet provided by Hugh, as I couldn't get any real feedback on whether the TKD was better than other attenuators I was considering (eg. Goldpoint ladders). I was also a little put off by the fact that the TKD was a series type attenuator but cost as much as the "ladder" types that (in theory at least) should be better. I liked the idea of 41 steps versus the more typical 20, but at the same time hated the idea of all those extra resistors in the signal path.

Having said all that, I know that Bob Crump/John Curl use the TKD in their apparently legendary CTC Blow Torch pre-amp (costing US$20k or something). Bob advised me that, with a small modification, the TKD is the best attenuator he has come across. Stock, he found it a little undynamic. He was happy to share the mod with me but doesn't want it published on the Internet. I'm sure it is no big secret, and you may even have tried it already, but e-mail me if you would like details.

Have you tried the TKD against ladder attenuators or DACT series attenuators etc ? How did it compare ?

It seems to me, just from reading other people's experiences (I haven't done any comparisons myself) that the end result seems to be more dependent on the "flavour" of resistor used (eg. Vishay/Dale, Holco, Roderstein, Tantalum, etc etc) than on the actual attenuator type (eg. series, shunt, ladder).....assuming appropriate impedance ratings etc.  Does this match your experience ?

Cheers,
Darren.

[mb]

Hi DSK,

mb,
I see you are using the TKD 41-step series attenuator. I  considered this while designing my GK-1. For the moment I am using the cermet provided by Hugh, as I couldn't get any real feedback on whether the TKD was better than other attenuators I was considering (eg. Goldpoint ladders). I was also a little put off by the fact that the TKD was a series type attenuator but cost as much as the "ladder" types that (in theory at least) should be better. I liked the idea of 41 steps versus the more typical 20, but at the same time hated the idea of all those extra resistors in the signal path.

AFAIK, it's not a series attenuator. I would never have forked out the $$ if it was the case. I've opened it up. 4 beautiful rows of TKD resistors.

Having said all that, I know that Bob Crump/John Curl use the TKD in their apparently legendary CTC Blow Torch pre-amp (costing US$20k or something). Bob advised me that, with a small modification, the TKD is the best attenuator he has come across. Stock, he found it a little undynamic. He was happy to share the mod with me but doesn't want it published on the Internet. I'm sure it is no big secret, and you may even have tried it already, but e-mail me if you would like details.

Email on the way! Thanks.

Have you tried the TKD against ladder attenuators or DACT series attenuators etc ? How did it compare ?

It seems to me, just from reading other people's experiences (I haven't done any comparisons myself) that the end result seems to be more dependent on the "flavour" of resistor used (eg. Vishay/Dale, Holco, Roderstein, Tantalum, etc etc) than on the actual attenuator type (eg. series, shunt, ladder).....assuming appropriate impedance ratings etc.  Does this match your experience ?

Cheers,
Darren.

I haven't done enough comparisons for any substantial comments. My main point is the difference between attenuator alone, and attentuator followed by a good buffer. Night and day. To some ears, it beat the GK-1, albeit one that was not run in at all.

[Vinnie R.]

If you are that kind of persons who can not sleep with a pot in the signal path, you will certainly "go active again" with your new attenuator to see how it would sound in a highly spoken pre, like GK-1, within "the next 2 years". Believe or not.

You haven't tried your attenuator in any active pres, have you?

Larry,

I was using the preamp section of my NAD C370 Integrated Amp (which is pretty much the C160 preamp) before I switched to a passive 10k stereo pot.  I'm sure either one of the AKSA preamps would blow this
away though.

Getting back to your point, you are correct, as I am already thinking about the TLP    However, for now, I want to try a high quality passive preamp (stepped attenuator) and hear how that sounds.  
Another "budget" passive preamp that gets great reviews is the
Channel Islands VPC-1, which uses a high quality 10K pot and
allows for two sets of inputs.  Choices, choices.....